For all of our technical wizardry, human survival relies on a thin layer of soil, seeds and the occasional thunderstorm, Cary Fowler told the TEDGlobal audience in Oxford. It is a picture of the delicate balance that nurtures life on Earth, and while the planet warms, Fowler is working to save a critical element that will allow humanity to cope with global warming: biodiversity.

Fowler is one of the driving forces behind an international seed bank on the Arctic island of Svalbard to save 500 seeds from as many species as possible to help agriculture cope not only with global warming but also pests and disease.

This genetic resource stands between us and a catastrophic loss we can barely understand.

Crop diversity is the biological foundation of agriculture, but that foundation is crumbling as mass extinction destroys biodiversity and with it the genetic building blocks that could allow us to create new strains of crops.

To give a sense of the rate of loss, in the 19th century, farmers grew 7,100 named varieties of apples, but 6,800 of those varieties are now extinct.

Your ancestors gave greatest honour they could give to these apples. They gave them your name.

In many audiences, he passes around the list of extinct varieties and asks people if they can find their names among the apples on the list, and two-thirds of most audiences hold up their hands.

For those whose names remain on the list of apple varieties, he challenges them to make sure their varieties don't go extinct.

His namesake apple, the Fowler apple, is still cultivated. Pulling out a book from 1904 of apples grown in the state of New York, the Fowler apple is described as a beautiful fruit, but it is also noted that "it fails to develop in size and quality and is on a whole unsatisfactory".

There is no best variety, but "today's best variety is tomorrow's lunch for a pest," he said. "Maybe that apple has a trait that we will need tomorrow to deal with climate change."

Diversity: Think of it as giving us options. That is exactly what we need for climate change.

The coldest growing seasons of the future will be hotter than the hottest in the past. By 2030, climate change in South Africa is expected to decrease maize harvest by 30%. The reduction in harvest as population continues to grow will create a food crisis.

That is one of the reasons to build the seed bank in Svalbard. The other is the loss of seed banks around the world. Banks in Iraq and Afghanistan have been lost in the wars there, others have been lost to financial mismanagement or natural disaster. The facility at Svalbard hopes to provide protection against these losses.

This is a back-up system for world agriculture.

Some people have described it as a Doomsday Bank, but the need isn't in the distant future. "We're losing diversity everyday," he said.

Fowler said that he couldn't look the audience in the eye and say that he has a solution to climate change or a solution to the problem that agriculture uses 70% of the world's fresh water. However, he added, "By saving crops, we might end up saving ourselves."